How to remove text from an object

How to remove text from an object

Hi, 
I have an object that onmouseover - displays information.
I am using  element.append method to do that.

However, before doing that, I want to clear the object so it displays present content only.
Could not find anything like that. Well I found:

jQuery.removeData(elementName,[name])

and used it, b ut it doesn't work.
Any idea how I can do this simple thing?
Thanks.